Radio controlled plural motor crane control system



R. N. NICOLA July 26, 1966 RADIO CONTROLLED PLURAL MOTOR CRANE CONTROLSYSTEM Filed Feb. 26, 1963 7 Sheets-Sheet 1 7 Sheets-Sheet 2 R. N.NICOLA July 26, 1966 RADIO CONTROLLED PLURAL MOTOR CRANE GONTROL SYSTEMFiled Feb. 26, 1963 ATTORNEYS 7 Sheets-Sheet 3 R. N. NICOLA RADIOCONTROLLED PLURAL MOTOR CRANE CONTROL SYSTEM July 26, 1966 Filed Feb.26, 1963 ATTORNEYS July 26, 1966 R. N NICQ| A 3263141 RADIO CONTROLLEDPLURAL MOTOR CRANE CONTROIJSYSTEM Filed Feb. 26, 1963 7 Sheets-Sheet 4FIG. 5

INVENTOR.

S RENATO N. NICOLA ATTORN EYS 7 Sheets-Sheet 5 July 26, 1966 R. N.NICOLA RADIO CONTROLLED PLURAL MOTOR CRANE CNTROL SYSTEM Filed Feb. 26,1963 R. N. NICOLA RADIO CONTROLLED PLURAL MOTR GRANE CONTROL SYSTEMFiled Feb. 26, 1963 7 Sheets-Sheet 7 United States Patent 3263,141 RADIOCONTRQLLED PLURAL MOTOR CRANE CONTROL SYSTEM Renato N. Nicola,Manchester, Conn. assignor, by mesne assignments, to Kaman AircraftCorporation, Bloomfield, Conn., a corporation of Connecticut Filed Fel).26, 1963, Ser. No. 261,029 20 Claims. (Cl. 318-16) This inventionrelates to motor control systems for material handling apparatus andmore particularly to a system for remotely and selectively operatingindustrial cranes.

Theutility of the present invention extends to various types of cranesand similar material-handling equipment but it is particularlyapplicable -to overhead cranes which are necessary -tools in a varietyof fields, particularly heavy industries such as the steel, automotive,electrical equip ment and shipbuilding industries. As its name suggests,an overhead crane is mounted above the work area on a supportingstrueture. Most overhead cranes are designed to move materials alongthree axes-up and down, back and forth, and sidewaysbut some cranes arelimited tomovement along only one horizontal path. For convenience theinvention is descri-bedhereinafter in connection with overhead cranesproviding material handling movement along the three descrbed axes. Atypical three axes overhead crane comprises a bridge unit which ismovable back and forth on parallel horizontal tracks, a trolley unitwhch is moi1nted on the bridge unit above ground level and is movablehorizontally relative to the bridge unit in a direction at right anglesto the bridge tracks, and a hoist unit mounted on the trolley andproviding controlled vertical movement to a materials holding elementsuch as a hook or bucket. Each of the three units nray -be driven by itsown electrc motor or, as an alternatve measure, one motor may operateall three units through separate selectively oontrollable drives.

Heretofore three general types of control systems have been availablefor overhead cranes. One type is the manin-cab system whch requires thatthe operator be situated in a cab mounted on the crane above the workarea. This type of control system is expensive and is used primarily onlarge cranes or where it is unsafe or unfeasible for the operator to beat ground level. A second conventional type of crane control is thependant c-or system, so called because the operating controls aredisposed in a control box whch is attached to the bottom end of a corddangling from the crane. The pendant cord control box is atwaist-to-shoulder level from the ground and the operator walks with thecontrol box in hand asthe crane moves under his control. While thependant oord system is less expensive and more convenient to use thanthe man-in-cab system, it is limited to installations Where the operatorcan walk unimpeded and safely in proximity to the crane. The thirdsystem involves a stationary control box at a .predetermined location.Its limitations are many, all stemming from the fact that the operatorcannot move with the crane. In recognition of the limitat-ions of theforegoing conventional control systems, there has been expressed theneed to provide a remote control system whch would give the operatorcomplete control over the crane while simultaneously permitting him tomove about the work area independently of the crane. A1- though radiocontrol is the likely solution, prior at-tempts to achieve a'satisfactory remote control system for cranes have been fruitless, dueprimarily to electrical interference, lack of dependabilityandinsufiicient operator control,

Accordingly the primary object of the present invention is to provide aremote control system for a crane whch permits movement of the operatorindependently of the crane while simultaneously assuring complete andaccurate control thereover.

A more specific object of the present invention is to provide formaterials handlng ap paratus having a plurality of motor-operated units,a remote control system whch permits selective control of each unit whenoperting alone or simultaneously with an-other unit.

Another specific object of the present invention is to provide a remoteradio control system for cranes and the lilce which is oprative withoutinterferehbe from nearby electrical equipment or stryelectromagheticradiation.

Described briefly a remote control system embodying the presentinvention will comprse a mobile manually controlled transm-itter and areceiver installed on the ap" paratus to be controlled such as anoverhead crane. The transmitter is adapted to generate a carrier signal,modulate the carrier signal with information pulses dstinguishableaccording to information, and radiate the pulse modulated carrier to thereceiver. The latter is adapted to dernodulate the carrier to extractthe inforr'naton pulses; distir1guish the pulses according toinformation, and cause -appropriate units of the crane to remaininoperative or to operate in one of two predetermined ways acoording tothenature of the information represented 1by the extracted pulses. Thetransmitter is adapted to produce separate informatio-n pulse waveformsfor the controllable units of the crane. These waveforms ditfer by pulsewidth and their pulses occur at different equally spaced -times withoutany time overlap between them. The same waveform is used for bothdirections of movement of the particular crane unitto whch it isrelated, this being possible by automatcally changing the pulse widthaccording to clirotion'. In a preferred embodiment of the invention, theseveral waveforms are mixed and the re sultantn'aixed pulse waveforrriis then used to modulate an R.F. sub-carrier, e.g. kc. The modulatedsubcarrier is then usedto modulate a UHF carrier, e.g. 465 mc., which isradi-ated to the receiver. Because of its frequncy the radiated carriermakes possible line-of-sight communication between the transmitter andthe receiver. Mreover} since the carrier has a short wavelength, theantennas need not be large, therebymaking it possible for the entiretransmitter to be carried by the operator; The receiver has a detectorwhch extracts the informati-on pulses and applies them to associatedci1cuitry whch separates the extracted pulses ace-ording to thecontrollable crane units to whch they relate. With these determnationsaccomplished the pulses are then used to cause the crane units to whchthey relate to perate in the apptopriate direction. Means are providedto prevent operation of the crane units in the ahsence of informationpulses or in response to stray pulses detected by the receiver. Thesystem is adapted to be battery powered and also can be designed tooperate more than one receiver from .a single transmitter. By means ofthe invention it is possible to remote control not only the directionbut also the speed of a plurality of reversible multi-speed motors.Other objects and many of the attendant advantages of the inventibn Willbe readily appreciated as the inventoh' becomes better understood byreference'to the following detaild description when considered inconnection with the accompanyng drawings wherein: FIG. 1 is a -blockdiagram of a portable trai1 smitter of a preferred embodiment of theinvention;

FIG. 2 is a timing diagram of significant waveforms produced inditfetent stages of the transmitter unit of FIG. l;

FIG. 3 is a block diagram of the receiver unit of the preferredembodiment of the invention;

FIG. 4 is a timing diagram of pulse waveforms occurring at differentstages of the receiver unit of FIG. 3;

FIG. 5 is a circuit diagram of one of the pulse discriminating channelsembodied in the receiver unit of FIG 3.

FIG. 6 is a block diagram of the transmitter of another embodiment ofthe invention;

FIG. 7 is a timing diagram of significant wavefonms produced indiflerent stages of the transmitter of FIG. 6;

FIG. 8 is a circuit diagram of one of the manually controlled signalgenerating stages of the tranmitter of FIG. 6; and

FIG. 9 is a block diagram of the receiver unit used with the transmitterof FIG. 6.

Turnin-g now to FIGS. 1 and 2, the transmitter com prises afree-runninggenerator or clock identified generally at 2 which simultaneouslyproduces three identical frequency pulse waveforms K K and K each havinga period which may be considered as conssting of fo-ur equal timeincrements t which commence at times t t 2 and t I-Iowever, the threewaveforms are out of phase with each other, waveform K having a pulse attime wavetorm K having a pulse at time t and waveforrn K having a pulseat time t No pulse ocours at time t The generator 2 may take variousfiorrns but it is preferred that it comprise a free-runningmultivibrator 4 each side of which feeds a square wave output to a diodematrix 6 and one side of which feeds a square wave output to a flip-flopbinary counter 8. The two sides of the latter feed outputs to the diodematrix 6. T he matrix generates wavefor=rns K1, K and K at differentoutput points according to the relative pol-arities of the inputsthereto from the multivibrator 4 and the counter 8.

The pulse waveforms K K and K are applied to separate single shotrnultivibrators H, B and T which are operatively controlled bysingle-pole three posit-ion control switches 10, 11 and 12 respectivelywhose functions rare dentified by the terms Hoist, Bridge and Trolleyrespectively. Each switch has a center off position and two closedpositions. The two closed positions of the hoist switch 10 are labelledUp andDown, those for the Bridge switch 11 are labelled Forward andReverse, and those for the Trolley switch 12 are labelled Left andRight. When switch 10 is in the Up posi tien, the multivibrator Hproduces a pulse train H having thesame freqeuncy and phase as waveformK When switch 10 is in the Down position, the multivibrator H produces apulse train H having the same frequency and phase but twice the pulsewidth as pulse train H When switch 11 is in the Forward position themultivibrator B produces a pulse train B having the same frequency andphase relationship to pulse train H as waveform K has to wavef-onm K huthaving a pulse width three times as large as that of pulse train H Whenswitch 11 is in the Reverse position, multivibrator -B produces a pulsetrain B having the same frequency and pl1ase as pulse train" B but apulse width tour times as large as that of pulse train I-I When switch12 is in the Left position, multivibrator T produces a pulse train Thaving the same frequency and =phase relationship -to pulse train B aswaveform K has to Waveform K but having a pulse width which is fivetirnes as large as that of pulse train H Moving switch 12 to the Rightpositon causes multi vbr-ator T to produce -a pulse train T identical infrequency and phase to pulse train T hut having a pulse width which issix tirnes as lange as that of pulse train H The means by which thesemultivibrators are made to have two different pulse widths are describedlrereinafter in connection with FIG. 8.

The outputs of the three single shot multivibrators are fed to a mixer14 where they are combined to form a mixed output signal. In FIG. 2 thewaveiorms M is representative of the mixed signal which results When thesignals represented by waveonrns H B and T are fed to mixer 14. Thismixed output is fed to a modulator 16 where it modulates a kc.sub-carrier signal generated by an oscillator 18. The modulated 100 kc.signal is then fed to a modulator 20 where it modulates a 465 mc.carrier generated by a second oscillator 22. The modulated carrier isradiated by an -antenna 24 to a complementary receiver unit installed ona crane. This antenna is supported by and portable with the transrnitterunit.

The power supply for the above-described transmitter unit comprises a 12volt battery pack 26 coupled by a double pole single throw switch 28 toa D.C. to D.C. converter 30 which provides a higher voltage output tothe two oscillators via a panic switch 32. Battery power is supplied tothe other stages of the transmitter via leads 34.

Turning now to FIG. 3, the complementary receiver comprises an antenna40 which receives the radiated carrier and couples it to a 465 mc. tunedamplifier 42. The latter amplifies the received signal and applies it toa detector 44 where the 100 kc. signal is extraoted fuom the carrier andapplied to an amplifier 46 tuned to 100 kc. After amplfication the 100kc. signal is fed to a second detector 48 which generates an outputwhose D.C. level is proportional to the strength of the carrier signalreceived by antenna 40. This output is used to fire a Schmitt triggercircuit 50 whose output is fed to a driver circuit 52 for a relay 54used to control application of electric power from a .suitable source56. The driver circuit 52 is essentially a current amplifier. If thereceived carrier signal is above a predeter mined safe level, the outputof detector 48 will have a D.C. level suflficiently high to fire theSchmitt trigger, whereupon the relay driver 52 will energize relay 54.II will keep it energized until the strength of the received signalfalls below the predetermined threshold level, at which point theSchmitt trigger will reverse itself and thereby the output of driver 52will be insuiicient to keep the relay energized. When relay 54 isenergized its contacts close to connect electric power to the motorcircuits of the crane under the control of the receiver circuitshereinafter described. When relay 54 is de-energized, its contactsreturn to the open circuit position sho-wn in FIG. 3.

The output of the 100 kc. tuned amplifier 46 also is applied to -adetector and pulse shaper circuit 60 which extractsthe informationpulses from the 100 kc. subcarrier, inverts them, and shapes them forsubsequent use. These information pulses are then applied to a singleshot multivibrator 62 which produces a control gate pulse CG (FIG. 4)coincident in time with the trailing edge of each information pulsereceived frorn the pulse shaper. Simultaneously the same informationpulses are fed to six parallel pulse discriminating units eachcomprising a single shot multivibrator 64, an inverter sta-ge 66 whichincludes a diferentiating circuit on its input side, a gate 63, a shaper70, a detector 72, a relay drive 74, and a motor control relay 76. Thesesix pulse discriminating channels are identical except for the outputsof ther rnultivibrators 64 which dier in the manner now to be described.

As indicated in FIG. 3 by the legend H I-I B B T and T each of themultivibrators 64 is related to a dierent one of the various species ofinformation signals shown in FIG. 2. This relationship is based on pulsewidth. By internal adjustment the multivibrators 64are made to produceoutputs of different pulse widths. In response to the leading edge ofeach informaton pulse received trom shaper 60, the H multivibrator 64will produce a pulse startng at the same time as its input and having apulse width almost but not quite as large as that of pulses H (FIG. 2)produced by the multivibrator H of the transmitter (FIG. 1). At the sametime the H multivibrator 64 will produce a pulse having a pulse widthalmost but not quite as large as that of the pulses H produced bymultivibrator H. The pulses produced by the H multivibrator 64 will bewider than those produced by the H multivibrator 64. Simultaneously theB B T and T multivibrators 64 will produce pulses whose pulse widths areprogressively larger and are almost but not quite as wide as the widthsof the B B T and T pulses respectively generatedby the transmittetmultivibrators B and T. The outputs of the multivibrators 64 aredifferentiated in the inverters66 to get narrow pulses intimecoinoidence with their trailing-edgs. After inversion these narrowinformatioh pulses are app-lied to the gates 68. For convenience theindivdual gates 68 and their outputs are identified nFIGS.3 and 4 by thedesignations G G G G G andG and the narrow information pulses appliedthereto by; the inverters 66 are identified in FIG. 4.by the designatonsRH RH RB RB RT and RT respectively. As seen from a comparison with thetopmost waveforrn nFIG. 4. which illustrates the relative Widths andstartng ;ti mes of the information pulses that are transmittedto thereceiver, the pulses RH span the trailing edgs of the received pulses Hand the pulses RH span the;trailing edges of the received pulses H Thesame time 1elationshipjexists between the pulses RB RB RT and R'I andthe received pulses B B T and T These relationships are due to the factthat the pulses RH RT are delayed from the leading edges of thetransmitted pulses by the time duration of the outputs from the singleshot multivibrators 64. At this point it is to be observed that thereason for making the outputs of rnultivibrator 64 slightly less inwidth than the transmitted information pulses to which they are relatedis to make sure that delays caused by circuit parameters will notprevent gate pulses RHRT from occurring in time coincidence with gatecontrol pulses CG which are generated directly by the trailing edges ofthe'received information pulses and applied to each of the gatingcircuits 68. Each gating cir cult 68 produces 'ari output pulse onlywhen it receives an information gate pulse in time coincidence with acontrol gate pulse CG. As previously stated, the waveforms G to G inFIG. 5 illustrate the outputs of gating circuits G G respectively.

The outputs of the six gating circuits G G are fed via pulse shapingcircuits 70 to separate detectors 72 which are adapted to integratesuccessive pulses. The D.C. outputs of the detectorsare applied to therelay drives 74 -to operate motor control relays 76.- Each of the relayshas a pair of normally open contacts 78 and a pair of normally close dcontacts 80 which close and open respectively when the relay isenergized by the output of the relay drive associated therewith. Eachrelay drive 74 wi=ll r1ot operate its related relay 76 until the D.C.output of its related detector 72 reaches a predetermined level, whichlevel is reached only if a predetermined number of pulses are integratedwithin a predetermined period. Inpractice each relay drive is designedto operate the relay only When ten successive pulses have beenintegrated within a predetermined short time period.

The relays 76 are arranged to couple power in parallel to three separatereversible motors a hoist motor MH, a bridge mot-or MB and a trolleymotor MT-from the crane power source via the cranepower relay 54. Tothis end relays 76 are arranged in pairs. Each relay of each pair hasits normally closed contacts 80 connectedbetween relay 54 and thenormally open contacts of the other relay of the same pair. The two setsof normally open contacts 78 in each pair of relays are connected to thedirectioncontrolling contactors(not sh own) of the same reversible motorso that the motor will operate in one direction or the other, dependingupon which relay of the pair is energized. -As indicatedin FIG. 3, whenrelays 76 of the H B andT sign al channels are energized, thehoistbridge and trolley motors Will operate in the Up, Forvvard ;and;Leftdrections respectively, and vvhcn the relays 76 of the H B and T signal9 h QQ ll l i the Down, Reverse.and Right directions respectively. FIG.5 shows in detail one of the pulse discriminating channels embodied inthereceiver system of FIG. 3.

Each of these channels compriseseight PNP transistors Q1-Q8. With theexception of transistors Q3, Q7 and Q8, all of the collectors areconnected to a common negative voltage supply V1 through appropriatedropping re sistors 92, 94, 96, 98 and 100. Q3 and Q7 operate as emitterfollowers and their collectors are connected directly to V1. Q8 is acurrent amplifier and its collector is connected to a secorid supplyvoltage V2 via the coil of one of the motor control relays 76. Inputpulses from the detector and shaper circuit 60 of FIG. 3 are applied tothe pulse discriniinator channel at a terminal 102 which is connected tothe base of Q1 by a capacitor 104 and a resistor 106 in the order named.The junction ofthe capacitor 104 and resistor 106 is connected to groundby a diode 108. The emitter of transistor Q1 is tied directly to groundtogether with the emitter of transistor Q2. The collector of transistorQ1 is coupled to the base of transisto'r Q3 via a resistor 109. A zenerdiode 110 is connected across the resistor 92 in the collector circuitof. transistor Q1.

The emitter of transistor Q3 is connected to ground by a resistor 112and is also connected to the base of transistor Q2 by a capacitor 114.The base of transistor Q2 is returned to the supply voltage V1 by aresistor 116 anda variable resistor 118. The collector of transistor Q2is coupled to the base of transistor Q1 via resistor 120.. The collectorof transistor Q2 is also connected to the base of transistor Q4 by acapacitor 122 anda resistor 124. The base of transistor Q4 is alsoconnected to the supply voltage V1 by a resistor 126. The emitter oftransistor Q4 is connected to ground. The collector of transistor- Q4isconnected by a diode 128, a ciapacitor 130, and a resistor 132 in theordernamed tothe base of transistor Q5. A.diode 134 is connected betweenground and the junctionlbf capacitor and resistor 132. connected to thejunctiori of diode 128 and capacitor 130 is a diode 136 which is-connected at its positive end to an inputterminal 138 to whichisappliedthe output of the single shot rnultivibratdr 62 (FIG. 3) whichgenerates the gate control pulse CG. Connected to thejunction ofcapacitor 130 and diodes l28and 136 is a resistor 140 leading to thesupply voltage V1. V

The emitters of transistors Q5 and Q6 are both connected directly togrond. '1he collector. of transistor Q5 is connected to the base oftransistor Q6 by a capacitor 142. The base of transistorQ5 isc0nncctedto the collector of Q6 via aresistor 143. The base oftransistor Q6 is also connected t o supply. voltage V-1 by a resistor144. The collector of transistor Q6 is coupled to the base of transistorQ7 by a capacitor 146 and a diode 148 in the order namcd. The junctionof capacitor 146 and diode 148 is connected to ground by a resistor 1501The base of transistor Q7 is connected to ground by a capacitor 152 andthe emitter of the same transistor is connected to grot1nd by a resistor154. The emitter of transistor Q7 alsoiscoupled to the base oftransistor Q8 by a resistor 156. The emitter oftransistor Q8 isconnected d-irectly t0 ground. The emitter of Q8 is also connected tothe supply voltage V2 by a capacitor 158 and a diode 160 in theordernamed.

In the circuit first described the transistors Q1Q3 comprise a firstsingle shot multivibrator, the capacitor 122 and resistorl24 comprise adiiferentiating circuit, the transistor Q4operates as an i1verter, thediodes 128 and 136 function as an and gate, the stage ofitransis- -torsQ5 and Q6 constitutes a second single shot multivibrator which functiohsas a.wave shaper, the stage of transistor Q7 fimct-ioris as adetector,and; the circuitof transistor Q8 cmprises a driverstage for relay 76.The transistors Q3 and Q7 are connected as lemitt er folloWer s tofacilitate jproper impedance matching. ;The zener put pulses from thefirst multivibrator Q1-Q3 is set by mans of the variable r'esistr 118.

Operation of the circuit of FI G. is as follows: a squ;re negativeinformation 'pulseapplied to terminal 102 from the detector and pulseshaper 60 of FIG. 3 appears at the base of Q1 and the collector of Q2 asa sharp negative spike due to the dilerentiating action of capacitor 104and resistr 6, This spike is in phase withthe leading edge of thesign-al appl ied to terminal 102. The multivibrator comprisingtransistors Q1, Q2 and Q3 operates through acomplete cycle whentriggered with the negative spike. The substantially square output pulseof the multivibrator is diierentiated. by capacitor 122 and resistor 124to yield sharp negative and positive spikes(FlG. 5)coincident in timewith its leading and trailing edg es respectively. The positive spike isamplified and inverted by transistor Q4. The transistor Q4 produces anegtive square gate pulse which is added to the negative Square gatecontrol pulse CG applied to terminal 138. Whenthese gate puls es havetime coincidence, the mult-ivibrator Q5, Q6 is fired to produc arelatively wide negativesquare pulse. This pulse is applied to the baseof transistor Q7, charging up the capacitor 152. When the capacitor 152h-as been charged to the proper level by a succession of pulses, thetransistor Q7 will conduct and caus Q8 to energize thereby. Thetransistor Q7 will continue to conduot as long as the voltage oncapacitor 152 is suflicien t ly negative. If the pls es received by thebase oftransistor Q7 are interrupted, capacitor 152 will begin todischarge through the transistor Q7 and the resistor l 54 andits voltagewill decrease sufficiently to terminate operation of Q7 and therebydeenergize the relay. Q7 will remain nonconductinguntil diode 148 hasagai n p assed aseries of pulses suflicientto charge cpacitorl52 up tothe af oresaid proper level. The capacitor 158 acts to kill anyripple.while the diode 160 acts as a damper.

It is believed to be apparent that the system shown in FIGS. 1 and3permits diree tiorial control of three motors simultaneously,eachoperating at a single speed of operation. Moreover using the sameprinciples, the invention is adaptable to controlling more than -thre emotors at more than one speed, An dditional motor may be controlled withonly minorhanges -because of the fact that the timing period shown n FIG2 includes a time interval commencing at time I.; which is unused. Thistime interval may be used for a direction information pulse relating toa fourth motor. Extending the abovedescribed system so as to operate oneor more. motors at,any one of a plurality of speeds is made possi-hle byreserving for each motor an. information time interval substantiallylarger than the time interval required for the pu1ses H T justdescri-bed so as to accommodate an additional pulse which determines thespeedo f -operation of the same motor The exact speed atwhich aparticular motor is to be operatedmay behdet errnined by the pulsewidthof the speed informaton pulse, Such a system is illustrated in FIGS.6-9.

FIGS. 6 thrbugh 9 show a system for controlling a crane having fourmotors eachadapted to operate at any one of five speeds. One motoroperates the bridge, 'another motor operates the-trolley, and the other.two motors operate separate hoists.

Turning now to FIG.- 6, the transmitter of. the multispeed systemcomprises a free running generator or clock taking the form of a freerunning multivibrator 170, each side of which feed s a square waveoutput to a diode matrix 172 and one side of which feeds a square waveoutput to a flip-flop binary ,counter.l74. Output s .are sfed fromthetwo sides of the flip-flop counter174to the diode matrix 172. The diodematrix generates tour identical frequency pulse waveform s which are outof phase with each other, one waveforrn having a pulse at time t anotherwaveform ha ving a pulse at time t the third waveformhaving a pulse attime i and the fo1rth waveform having a pulse at time t Thetiming pulsesgenerated by the diode matrix are used to key four groups of singleshot.multivibrators each controlled by a pair of manually aetuatedswitch units. These switch units are illustiatedschematically in FIG.6at 178, 180, 182, 184, 186, 188, 190 and 192. Inpractice these switchunits are enrbodid in a single controlboxwith the functionand sttings ofachi1nit designated by appropriate legend.

Switch unitl78controls the starting and stopping and also the directiono fi the motor ofhoist1 and switch unit 180 controls the speed of thesame motor. Operatively associated with switch units 178 and 180 arethree single shot multivibrators SS SS and SS The function of the singleshot multivibrator 88 is to produce an information pulse whichdetermines whether the motorof hoist 1 is to operatie in the up or downdirection. This function is indicated by the lege nd H1 in FIG. 6.Multiviorator SS, operates in response to the pulse output trom diodematrix 172 which occurs at time t Multivibrator SS operates in responseto the output of multivibrator 88 The output ofmultivibrator is used tooperte multivibrator SS Multivibrator SS functions as a delay element,causifig multivibrator SS -to operate a predetermined time interval-after niultivibrator SS Switch unit 178 is the same as swithes 10, 11and12 of FIG. 1 being essentially a thre e position switch with oneoipositin and two closedpositions. The closed positions are identifiedas up and down? When the switch 178 is in the up position, multivibratorSS will produce a pulse of predetermined width at time t and whentheswitch 178 is in the down position, the same multivibratorwillproduce at time t a pulse whose width is twice theaforesaidpredetermined width. Thisrelationshi-p is seen in BIG. 7 by the waveformidentified as H1 The pulse width shown in full lnes is the pulsegenerated whenswitch178 is in theiup position and the pulse indicated bythe broken line is the one generated when switch 178 is in the downposition. The other switch unit 180 is adapted to permit nanualselection of fivediierent switch settings, a dierent setting for eachmotor speed. Normally switch unit 180 is in the 1 or low speed setting.In this position, no pulse output is produced bymultivibrator SSHowever, when the switch unit 180is in the 2 speed setting multivibratorSS will produc e a pulse output which is delayed in time from the pulseoutput of multivibrator 85 by an amount determined by multivibrator SSMovng the switch unit 180 to the 3, 4 and 5 speed settings will causethe pulse output of multivibrator 58:, to decrease in width bypredetermined increment s. This relationship is shown in FIG; 7by thewaveform H1 The pulse shown in dark lines is the one generated wh enswitch unit 180 is in the 5 position. The ihcreasing pulse widths shownby the broken line s are characteristc of the switch settings 4, 3 and 2respectively. At thispoint it is to be observed frorhF1G. 7 that thepulse of the Waveform Hl commences after the pulse of th waveform -H1produced by the single shot multivibrator SS but termiriates before timet Switch unit 182 controls starting and stopping and also the directionof the motor of hoist 2. Accor dingly switch unit 18 2 is the same asswitch unit 178, but it c'ontrols oprationof a mltivibrator SS which iskyed by the pulse output"offthe diode matriir ccurring at time t Whenswitch unit 182 is in the up position, it causes multivibrator 88.; toproduce at time t a pulse whose width is thre timesithewidthof the pulseproduced at time t when the switch unit, 178 is inthe up-postion. Whenswitch unit 182 is in the down position, multivibr atorss produces ,attime -t a pulse which is fout .times as wide as the pulse produced bymultivibrator SS when switch unit 178 is in the up position. Thesepulses -are shown in FIG. 7 by the wavef0 rm H2 the width of the downpulse being shown in braken lines.

The output of multivibrator 85 is used to operate a multivibrator SSwhch controls operation of a third multivibrator SS Multivibrator SScorresponds in function to multivibrator SS causing the multivibrator 88to operate after a predetermined time delay. The multivibrator 88 isidentical to multivibrator S8 producing different widths according tothe setting of switch unit 184 which is identical to switch unit 180.The output pulse waveform of 83 is identified in FIG. 7 as H2 the pulseshown in dark lines representing the pulse width when the switch unit184 is in the 2" or second lowest speed position. The broken linesindicating how the pulse width narrows as the switch unit is movedthrough the 3, 4" and 5 positions in that order. The differentselectable widths of the H2 pulse differ by the same increments as thedifferent widths of the H1 pulse.

Switch units 186 and 188 are identical to switch units 178 and 180respectively but control the bridge motor. These units directly controlsingle shot multivibrators S8 88 and SS Multivibrator 58 is keyed by theoutput of the diode matrix occurring at time i The mutivibrator SS isoperated by the output of multivibrator 85 and in turn operates themultivibrator SS after a predetermined time delay. The three positionsof switch unit 186 are o, forward and reverse. In the off postion,multivibrator SS7 will not produce any output. In the forward" position,multivibrator SS will produce a pulse occuring at the time 1 having apulse width 5 times as large as the width of the pulse generated bymultivibrator SS when switch unit 178 is in the up position. When switch186 is in the reverse position, multivibrator SS will produce a pulsesix times as wide as the pulse produced by 88 when switch unit 178 is inthe up position. The output of 88 is shown in FIG. 7 by the waveform BThe multivibrator 859 is identical to multivibrators SS and SS producingpulses of four different widths according to the setting of switch unit188. The output wavefor-m of SS is shown in FIG. 7 at B The diferentpulse widths obtainable with multivibrator SS are the same as the pulsewidths obtainable with multivibrators SS and SS Operation of the trolleymotor is determined by switch units 190 and 192 which are identical toswitch units 186 and 188 just described except that the three positionsof switch unit 186 are designated oif, left and right. Operatvelyassociated with and controlled by these switch units are threemultivibrators S8 S5 and SS Multivibrator 85 is keyed by the output ofthe diode matrix occurring at time t Multivibrator 85 is operated bymultivibrator S8 and its output causes operation of mul tivibrator S8after a predetermined time delay. Multivibrator SS produces a pulseseven times as wide as the up pulse produced by multivibrator SS whenswitch unit 190 is in the left position and a pulse which is eight timesas wide when switch unit 190 is shfted to the right position. The outputof multivibrator SS is shown at T in FIG. 7.

Multivibrator SS is identical to multivibrators S5 88 and SS prducingpulses of the same several widths at corresponding positions of itscontrolling switch unit 192. The output waveform of S8 is shown at T inFIG. 7. FIG. 7 also shows how the direction and speed control pulses forthe same motor fall within the same time block and do not overlap intoadjacent time blocks. This is achieved by having the multivibrators SS;,S8 88 and SS introduce successively smaller amounts of delay tocompensate for the successively greater width pulses produced bymultivibratdrs S8 S8 S5 and S5 respectively. As used herein, a timeblock is the time interval:reserved for information pulses of one motor,e.g. the time t to time 1 in FIG. 7 pertaining to the motor of hoist 1.

Referring back again to FIG. 6, the outputs of multivibrators S5 S5 SSSS SS SS SS and SS are fed to a mixer 210 to produce a combined signalCS (FIG. 7) which is fed to an oscillator-modulator 224 where itmodulates a kc. sub-carrier signal. The modulated sub-carrier is fed toan oscillatormodulator 226 where it modulates a 465 kc. carrier. Themodu lated carrier is radiated by an antenna 228 to a comple mentaryreoeiving unit installed on a crane.

The power supply for the above-described transmitting unit isessentially the same as the power supply for the transmitting unit shownin FIG. 1, comprising a 12 volt battery pack 230 which is cowpled by adouble z pole single throw switch 232 to a D.C. to D.C. converter 234whch provides a higher voltage output to the two Oscillators via a panicswitch 236. Power to the other circuits is supplied via leads 238.

FIG. 8 is a circuit diagram of the multivibrators S8 85 and SS embodiedin the transmitter shown in FIG. 6. The illustrated circuit comprisesseven PNP transis tors Q9-Q15. Multivibrator SS comprises transistors Q9and Q10, andrnultivibrator SS comprises transistors Q12 and Q13, andmultivibrator SS comprises transisto-rs Q14 and Q15. Transistor Q11 isconnected as an emitter follower for proper irrupedance match betweenQ9, Q10, and Q12, Q13. Accordingly theemitter of Q11 is connected toground via a resistor 234 and its collector is connected directly to avoltage source V3, while the emitters of the other transistors aregrounded.

The base of Q9 is connected by a diode 236 and a capacitor 238 in theorder named to an input terminal 240 to which is applied the output fromdiode matrix 172 occurring -at time t Connected between ground and thetwo ends of diode 236 are resistors 242 and 244. The same input also isapplied to the collector of Q10 via a zener diode 250. The base of Q10is connected to ground by a resistor 252 and to the collector of Q9 by adiode 254 and. a capacitor 256. The junction of diode 254 and capacitor256 and the collectors Q9 and Q10 are connected by resistors 260, 262and 264 respectively to a voltage source V3 by way of a variableresistor 268 or another variable resistor 270 as determined by themanually operated switch unit 178. Resistors 268 and 270 are set so thatthe multivibrator output at the collector of Q10 will have aqaredetermined pulse width when switch unit 178 is closed to resistor168 and a pulse width two times as great when switch 178 is closed toresistor 170. The output is applied to the base of Q11. The signalaxppearing at the emitter of Q11 is applied to transistors Q12 and Q13and also to an output terminal 274 via a diode 276.

The signal trom Q11 is applied to the collector of Q12 via a capacitor278 and a diode 280. The collector of Q12 is connected to the base ofQ13 by a capacitor 282 and a diode 284. The bases of Q12 and Q13 areconnected to ground by resistors 286 and 288 respectively. A zener diode290 connects the base of Q12 and the collector of Q13. The junction ofcapacitor 278 and diode 280, the junction of capacitor 282 and diode284, and the collectors of Q12 and Q13 are connected to voltage sourceV3 by parallel resistors 294, 296, 298 and 300 respectively connected inseries with a nornially open switch 180a whch forms part of switch unit180. Transistors Q12 and Q13 will not operate unless switch 180a isclosed. If it is closed, an input pulse frorn Q11 will produce an outputpulse at the collector of Q13 after a time delay determined by thevalues of the RCcomponents connected to Q12 and Q13.

The output at the collector of Q13 is applied to the collector of Q14 bya capacitor 304 and a diode 306. Thecollector of Q14 is connected to thebase of Q15 by a capacitor 308 and a diode 310. The two bases areconnected to ground by resistors 312 and 314. Additionally the base ofQ14 is-tied to the collector of Q15 by a zener diode 318. The collectorsof Q14 and Q15, the junction of capacitor 304 and diode 306, and thejunction of capacitor 308 and diode 310 are coupled to voltage sour-ceV3 by parallel fixed resistors 320, 322, 324 and variable resistor 325respectively in series with three fixed resistors 326, 328 and 330 andswitch 180a. Cnriected in series with switch 180a across resistors 326,328 and 330 are normally open switches 18012, 180c and 180d respectivelywhich form part of switch unit 180. Switches 180a, b, c and-d arearranged to close in the order named and to reopen in the reverse order.Transistors Q14 andQl5 will not operate unless switch 180 is closed.When this occurs an output pulse will occur at the collector of Ql5 inresponse to a pulse input from the collector of Q13. When switch 180b isclosed, resistor 326 will be shorted out; this changes the RC value andthereby causes a reduction in the width of the output pulse occurring atthe collector of Q15. Successive closing of s witches 180c and 180dcauses the pulse width to be narrowed by two additional increments. Theoutput pulse is appled to output terminal 274 via a diode 334.

The other groups of multivibrators shown in FIG. 6 also embody thecircuit of FIG. 8 but with minor changes to achievethe desired pulsewidth and time delay. Altering the values of capacitor 256 and resistor260 permits adjustment of the width of the direction information pulsesgenerated by multivibrators SS;, 58 and 58 Varying the values ofcapacitor 282 and resistor 296 provides the delays effected bymultivibrators SS 58 and 88 Eliminating the multivibrator stages 88 and55 from the circuit of FIG. 8 yields a multivibrator circuitcorresponding to the multi vibrators H, B and T of the ernbodiment ofFIG. 1.

The receiver for processing the information signals of the transmittershown in FIG. 6 is shown in FIG. 9. This unit embodies essentially thesame stages as the receiver of FIG. 3, plus additional stages forhandling the speed information signals. Thus, as shown in FIG. 9, thereceiver comprises an antenna 350 which reoeives the radiated carrierand couples it to a 465 mc. tuned amplifier 352. The latter am1plifiesthe received signal and applies it to a detector 354 where the modulated100 kc. sub-carrier is extracted from the carrier and applied to anamplifier 356 tuned to 100 kc. After amplification the 100 kc. signal isfed to a second detector 358 which generates an output whose D.C. levelis proportional to the strength of thesignal received by antenna 350.This output is used to fire a Schmidt trig ger circuit 360 whose outputis fed to a driver circuit 362 for a relay 364 used to controlapplication of electric power to a plurality of motor control relaysfrom a suitable source 366. The driver circuit 362 is essentially aeurrent amplifier. Thus, as in the embodiment of FIG. 3, if the receivedsignal is above a predetenmined safe level, the output of detector 358will have a D.C. level suficiently high to fire the Schmitt trigger,whereupon the relay driver 362 will energizc relay 364. The relay 364will remain energized until the strength of the received signal iiallsbelow the predetermined theshold level, at which point the Schmitttrigger 360 will reverse itself and thereby the out-put of the drivercircuit 362 will be insuflicient to keep the relay energized. Thecontacts of relay 364 are normaily open and close only when the relay isenergized. Thus in the absence of a s1gnal having a strength above thepredetermined threshold level, no power will be transmitted to thecontrol circuits for the various motors of the crane.

The output of the 100 kc. tuned amplfier 356 also is appl1ed to adetector and pulse shaper circuit 368 which extractsthe informationpulses from the 100 kc. subcarrier, inverts them, and shapes them foruse by the control circuits now to be described. These control circuitsare pulse discriminator circuits like the one shown in FIG. 5, withcertain of the pulse discriminator circuits of FIG. 9 including anadditional gate circuit as hereinafter described;

The output from the detector and shaper 368 is appled Cil to each of sixpulse discriminator circuits 370 adapted to discriminate pulsesrepresenting motor direction and to operate relays 372 controlling motordirection. Each of the discriminators 370 is set to discriminate aparticular pulse width in the manner described previously in connectionwith FIGS. 3-5. The discriminators which handle the up signals for hoist1 and hoist 2 are identified as PD-H The discriminators for the samehoists which handle the down signals are identified as PDH Thediscriminators which handle the forward and reverse signals for thebridge are identfied as PD-B and PD-B respectively. The discriminatorswhich handle the left and right signals for the trolley are identifiedas PD-T and PDT To each of these discriminators is also fecl the outputof a single shot multivibrator 374 which produces a gate control pulsein response to the trailing edge of each information pulse passed by thedetector and shaper unit 368. The multivibrator 374 corresponds to themultivibrator 62 shown in FIG. 3.

In addition to controlling operation of motor direction control relays372, pulse discriminators PD-I-I PD-T monitor the received informationpulses to determine if a direction control information pulse isaccompanied by a speed control information pulse. If a speed controlpulse is determined to be present, it is allowed to pass to tourdiierent speed pulse discriminators 376 identified as PD-Z, 3, 4 and 5.The numeral following the designation PD indicates the motor speed whichis controlled by that particular discriminator. In this con nection itis to be observed that the same four speed pulse discriminators are usedfor the speed signals for both directions of movement of a particularmotor.

The only signals which reach the speed pulse discriminators are thespeed pulses, this control being made possible by applying the receivedinformation pulses to gate circuits 378, 380 which are controlled by thepulse discriminators PDH PDT These gates will pass information pulses tothe speed pulse discriminators only in time coincidence with enabling orconditioning gate pulses received from the pulse discriminators PD-I-IPDT For proper control the gates 378, 380 must be enabled long enough topass a complete speed pulse and must be disabled again before the nextdirection information pulse received from the detector and shaper 368.This control is achieved -by enabling each gate 378, 380 with the widepulse produced by the shaper stage of the associated discriminator 370,i.e. the wide pulse output occurring at the collector of transistor Q6in FIG. 5. Since this wide pulse output commences in time concidence orshortly after the trailing edge of the direction information pulse whichproduced it, it will occur before or at the same time as a speed controlpulse. By making the output of the pulse Shaper sufliciently wide, agate 378 or 380 will be enabled long enough to pass a speed controlpulse. On the other hand, the enabling pulses obtained from thediscriminator 370 must be sufliciently sharp to shut off the gates 378,380 before the time of the next information pulse. The outputs of thegates 378 and 380 are appled to the speed pulse discriminators by way ofOR gates 382. Simultaneously the output pulses passed by the or gates382 are fed to single shot multivibrator 384 which produces gate controlpulses in response to the trailing edges of said output pulses.Multivibrators 384 correspond in function to rnultivibrator 374.

The speed pulse discriminators 376 are the same as the discriminatorsPD-H PDT diifering therefrom only in the width of the pulses produced bythe multivibrator stages thereof, i.e. the output from the collector oftransistor Q2 in FIG. 5. The outputs of their multi vibrator stages areset to correspond in width to the widths of the speed control pulsesprovided by the complementary transmitter unit of FIG. 6. Only one speedpulse discriminator will produce an output at a time, depending upon thewidth of the speed pulse input, The speed pulse discriminators arecoupled to dierent speed select relays identified as a group at 386.These relays control the speed of the particular motor to which thespeed signals relate. When no speed signals are passed by the gates 378,380 the motors will operate at their lowest speed. When speed signalsare passed by gates 378, 380, the speed of the motors will be determinedby the width of the speed pulse, the widest speed pulse resulting in anoutput from the pulse discriminator PD-2 and the narrowest speed pulseresulting in an output from the speed discrimnator PD-5.

It is believed to be apparent that the system of FIGS. 6-9 afiordssimultaneously selective control of four variable speed motors locatedremotely from the operator. Moreover, like the system of FIGS. 1-5, theline of sight communication afforded by the high frequency of thecarrier permits automatic lockout of the receiver when the signal leveldrops below a predetermined value. Since the antennas are relativelysmall due to the short carrier wavelength, and because electronics lendsitself to miniaturization and solid state components, the transmittercan be made relatively small and compact. In practice the transmitter isadapted to be strapped on the operators back and the manually operatedswitches are assembled in a single box adapted to be hung on a belt atthe waist and having a cable which plugs into the transmitter pack.Alternatively the transmitter may be supported on a portable floorstand. A further advantage is that more than one transmitter may beprovided for each installation, thereby permitting alternative orsequential operator control. The receiver also is easy to mount on thecrane, being rugged and dependable. Due to the choiceof frequencies, themodulation of carrier and sub-carrier, and the requirement that apredetermined number of pulses be received for a relay driver toenergize a motor control relay, the receiver system is responsive onlyto signals transmitted by the transmitter under the operators control.

A further advantage is that essentially the same kind of pulsediscriminator may be used for the systems of FIGS. 3 and 9. In thisconnection it is to be noted that in practice the discriminators arefabricated as separate plug-in printed board units, with plug-inconnectors 390 and 392 as shown in FIG. 5 to facilitate application ofinformation and gate enablihg pulses to gate circuits 378, 380.

It also is contemplated that the multivibrators in the transmitterunits, e.g. multivibrators H, B and T in FIG. I, need not be adapted toproduce pulses of more than one width. Instead a different multivibratoreach diierent pulse width. Also to be understood is the fact that thesystem need not be designed for three or more motors. It may operateonly one motor. It also may handleone or more single speed and one ormore multi-speed motors simultaneously. The widths ofthe time blocksreserved for signals for each motor may be altered according to thedemands of the system.

A further advantage of the present system is that it is; adapted foroperation in a bandwidth of 462.525t0' 467 .575 megacy cles. Currentlythis is the Class B Citizens Radio Band which involves a minimum of FCClicen'sing problems and permits a power level which is satisfactory forthe industrial installations contemplated for the invention.

Also of paramount consideration are the cost and operating advantagesafforded bythe invention. Fewer persons are required. to achieve controlof a single crane where visib ilty of accessibility is limted. Moreoverthe control is instantaneous and no dangerous time lag is involved inrelaying signals. eliminated by permitting the operator to moveindependently and remotely of the crane;

The present system also is not limitedtotri-directional overhead cranes.It may be adapted for. cranes providing movement along only one or twoaxes. It also is applica- Danger to personnel is 7 ble to locomotives,derricks, vehicular cranes, power shovels, fork-lift trucks, laterallyand verticallymovable elevators, and related types of materials-handlingequipment Having described the invention, various modifications andimprovements will now occur to those skilled in the art. Therefore, theinvention disclosed herein should be generating a third train of evenlyspaced pulses displaced timewise from the pulses of said first andsecond trains, means for modulating said carrier with said pulse trains,and means for radiating the modulated carrier; said receiver comprisingmeans for receiving the radiated modulated carrier and for derivngtherefrom a detected signal constituting all of the pulses of said pulsetrain, means responsive to all of said pulses in said detected signal togenerate a control pulse train, means responsive to all of said pulsesin said detected signal to generate first, second and third pulsedtiming signals, means responsive to both said control pulse train andsaid first, second and third pulsed timing signals for extracting pulsesaccording to said original first, second third transmitted pulse trains,means responsive to extracted first train pulses for controlling one ofsaid motors, means responsive to extracted second train pulses forcontrolling a second one of said motors, and means responsive toextracted thirdtrain pulses for controllng a third one of said motors.

2. Thecombinaton of claim 1 wherein said transmitter includes means forvarying the pulse width of one of said pulse trains; and further whereinsaid receiver includes means for dscriminating the pulses of said onepulse train according to width, and means responsive tosaiddiscriminated pulses for reversing the direction of the respect ive oneof said motors whenthe width of said discriminatedpulses in said onepulse train varies by a predetermined increment.

3 Remptely controlled materials-handling apparatus comprising 1) anoverhead crane having a hoisting element and first, secondand thirddrive meansresponsive to applied electrical control signals for causingsaid hoisting element to move longitudinally, sideways and verti-- callyrespectively; (2) an operator-controlled transmitter remote from. saidcrane for radiating electrical command signals; and (3) a receivermounted on said crane for controlling -operationof said-drive means inresponse to command signals fromsad transmitter; said transmittercomprising means for generating three distinct pulse trains with eachpulse train consisting of evenly spaced pulses displaced timewise fromthe pulses of the other pulse trains, operator-controllable means forselectively initiati11g and terminating generation of said pulse trains,a mixer, means for applying said pulse trains to said mixer to produce amixed pulse signal train, means for generating a sub-carrier signal,means for modulating said sub carrier signal with said mixed pulsesignal train, means for generatng a carrier signal, means for modulatingsaid carrier signal with said modulated sub-carrier, and means forradiating said modulated carrier signal, said receiver comprising meansfor demodulating said carrier to recover said modulated sub-carrier,means for demodulating said sub-carrier to recover said mixed pulsesignahtrain; means for segregating the pulses in said recovered mixedpulse signal train to reconstitute said threedistinct pulse trains,first means responsve to one of said reconstituted pulse trains forapplying an electrical control signal to said first drive means wherebyto cause said hoist to move longitudinally for a distance determined bythe time duration of said one reconstituted pulse train, second meansresponsve to a second one of said reconstituted pulse trains forapplying another electrical control sgnal to said second drive meanswhereby to cause said hoist to move sideways for a distance determinedby the time duration of said second reconstituted pulse train; andthirdmeans responsve to a third one of said reconstituted pulse trainsfor applying still another electrical control signal to said third drivemeans whereby to cause said hoist to move vertically for a distancedetermined by the time duration of said third reconstituted pulse train.

4. Apparatus for remotely controlling a plurality of motors comprisingmeans for generating n trains of timi-ng pulses With each train having aperiod of kT, and out of phase with other trains of timing pulses by atime interval equal -to a whole multiple of T less than kT, n and k bengintegers with n i1-aving a maximum value equal to k, means forgenerating .a first motor control signal pulse in response to eachtiming pulse of one of said trains of timing pulses within a timeinterval T of said each timing pulse, means for generating like firstmotor control signal pulses in response to pulses of the rest ot said ntrainsof timing pulses, means for mixi-ng the trains of said first motorcontrol signal pulses to produce a mixed signal pulse train, means fortransmitting said mixed signal pulse train, means for reoeiving saidmixed signal pulse train and for reconstituti-ng, therefrom said trainsof first motor control signal pulses, means responsve to saidreconstitnted trains Oif first motor control signal pulses forcontrolling one mode of operation of a difierent motor With eachseparate reconstituted train of first motor controi sig-nal pulses,means for generating a second motor control signal pulse in response toeach pulse of said one train of timing pulses within a time interval Tof said each timing pulse b11i1 separated in time from the first motorcontrol signal generated by said each timing train pulse, means forgenerating like second motor control signal pulses in response to pulsesod: the rest of said n trains, means for m-ixing the trains of saidsecond motor control signal pulses with the trains of said first motorcontrol signal pulses where=by the transmitted mixed -signal pulse trainincludes both said first and second motor control signal pulsesgmeansforreconst-ituting said trains of second motor control signal pulsesfrom said received mixed signal pulse train, and meansuresponsive tosaid reconstituted trains of second motor control signal pulses r'orcontrolling a second mode of operation of a different motor With eachseparate reconstituted train of second motor control sgnal pulses.

5. Apparatus as defined by claim 4 wherein said first motor controlsignal pulses control the direction of movernent o said motors.

6. Apparatus as defined by claim 4 wherein said first motor controlsignal pulses control the.direction of moveme-nt of said motors and saidsecond motor control signal pulses control the speed of said motors.

7. In combination Wh a crane l1aving at least two operating motors, asystem for remotely controlling said motors comprising anoperator-controlled transmitter cated away from said crane and a cranereceiver; said transmitter having means for generating -a carriersig;nal, cfirst operator-controlled means for generating a first trainof periodic pulses, second operator-controlled means tor generating asecond train of pulses of like periodicity displaced timewise frompulses of said first train, means for modulating said carrier with saidrfirst and second pulse trains, and means forradiating said modulatedcarrier; said receiver having means for receiving said radiatedmodulated carrier and .for deriving thererfrom a detected signalconstituting all of the pulses of said transmitted pulse trains, meansresponsve to the leading and trailing edges of each of said pulses insaid detected sig nal for extracting pulses from said detected signalaccording to said first and second transmitted pulse trains, meansresponsve to extraoted first train pulses for controlling one of saidoperatirrg motors, and means responsive to extracted second train pulsesfor controlling the second of said operating motors.

8. (In oombination with a crane having at least two operating motors, asystem for remotely controlling said motors comprising anoperator-controlled transmitter 10- cated away [from said crane and acrane receiver; said transmitter having means or generating a carriersignal, first operator-controlied means for generating a [first train ofperiodic pulses having a first pulse Wdiih, second operator-controlledmeans for generatin-g a second train of pulses of second pulse widt=hand like periodicity displaced timewise from pulses of said first train,means modulating said carrier with said first and second pulse tra-ins,and means tot radiating said modulated carrier; said receiver havingmeans for receiving said radiated modulated carrier and for derivingtherefrom a detected signal constitut-ing all ot the pulses of saidtra=nsrntted pulse trains, means responsve to the trailing edge of eachpulse in said detected signal for generating control signais, meansresponsve to the leading edge of each pulse in said deteoted signal forgenerating first and second timing signals related respectively to saidfirst and second pulse widths, means responsve to said contro-l signalsand said first and second timing signals -for generating pulses in firstand second ohan-nels respectively according to said pulses in said firstand second transmitted pulse trains, means responsve to pulses in saidfirst ohannel f-or controlling one of said operatin.g motors, and meansresponsve to pulses in said second ohannel for controlling the second ofsaid operating motors.

9. In combinationwith a crane having at least two reversible operatingmotors, a system for remotely controliing the operation and direction ofsaid motors comprising an operator-controlled transmitter located awayfrom said crane and a crane receiver; said transmitter i1avin g meansfor generafing a carrier signal, rfirst operator-controlled means forselectively generating a first train of periodic pulses of either of afirst and second pulse Width, second operator-controlle-d means forselectively generating a second train of pulses of like periodicity ofeither of a third and fonrth pulse 'widths displaced timewise frompulses of said rfirst train, means modulating said carrier with saidfirst and second pulse trains, and means for radiatirrg said modulatedcarrier; said receiver having means for receiving said radiatedmodulated carnier and rfor deriving therefrom a detected signalconstituting all of the pulses of said transmitted pulse trains, first,second, third and fourth receiver pulse ohannels, means responsve to theleading and trailing edges of each pulse in said detected .signal forseleotively pulsing said first and second receiver pulse ohannels inresponse to first train pulses of said first and second pulse widthsrespectively, and cfor pulsing said third and -fourth receiver pulsechannels in response to second train pulses o said third and f-ourthpulse vvidths respectively, means operating said first motor in orwardand reverse directions in response to pulses in said tfirst and secondreceiver pulse channels respectively, and means operating said secondmotor in forward and reverse directions in response to pulses in saidthird and fourth receiver pulse channels respectively.

10. A system for remotely controlling the operation of a crane as inclaim 9 vvherein said receiver further includes means or providing asafety signal related to the stren gth of the received carrier, and atr-igger circuit responsve when said sarfety signal alls below apreselected level for precluding the operat-ion of both said rfirst andsecond motors in either -direction.

11. A system for remotely controlling the operation of a Crane as inclaim 9 wherein said receiver further includes means in each of sad fourreceiver pulse channels for precluding the operation of either of sadmotors in either direction before first receiving a preselected numberof pulses in the respective channel.

12. In combination with a crane having at least two reversible operatingmotors, a system for remotely controlling the operation and direction ofsad motors comprising an operator-controlled transmitter located awayfrom sad crane and a crane receiver; sad transmitter having means forgenerating a carrier signal, first operator-controlled means forselectively generating a first train of periodic pulses of either of afirst and second pulse widths, second operator-controlled means forselectively generatng a second train of pulses of like periodicity ofeither of a third and ourth pulse widths displaced timewise trom pulsesof sad first train, means modulating sad carrier with sad first andsecond pulse trains, and means for radiating sad modulated carrier; sadreceiver having means for receiving sad radiated modulated carrier andfor deriving therefrom a detected signal constituting all of the pulsesof sad transmitted pulse trains, first, second, third and fourthreceiver pulse channels, a control circuit for providng a control pulseof uniform duration commencing with the trailing edge of each pulse insad detected signal, first, second, third and fourth timing circuits allsimultaneously actuated by the leading edge of each pulse in saddetected signal and provding timing pulses commencing briefly before andterminating briefly after the trailng edges of sad transmitter pulses ofsad first, second, third and fourth pulse widths respectively, gating,means actuated by the outputs of sad control and timing circuits forselectively pulsing sad first and second receiver pulse channels inresponse to first train pulses of sad first and second pulse widthsrespectively, and for pulsing sad third and fourth -receiver pulsechannels in response to second train pulses of sad third and fourthpulse widths respectively, means operating sad first motor in forwardand reverse directions in response to pulses in sad first and secondreceiver pulse channels respectively, and means operating sad secondmotor in forward and reverse directions in response to pulses in sadthird and fourth receiver pulse channels respectively.

13. A system for remotely controlling the operation of a crane as inclaim 12 wherein sad third and fourth transmitter pulse widths are bothgreater than sad first and second transmitter pulse widths.

14. In combination with a crane having at least two operating motors, asystem for remotely controlling the operation, direction -and speed ofsad motors comprising an operator-controlled transmitter located awayfrom sad crane, and a crane receiver; sad transmitter having means forgenerating a carrier signal, first operator-controlled means forselectiveiy genera-ting a first train of periodic pulse groups, secondoperator-controlled means for selectively generating a second train ofpulse groups of like periodicity displaced timewise trom pulse groups ofsad first train, pulses in each of sad groups in sad first and secondpulse trains having preselected pulse widths characteristic of directionand speed respectively, means for modulating sad carrier with sad firstand second pulse trains, and means for radiating sad modulated carrier;sad receiver having means for receiving sad radiated modulated carrierand for deriving therefrom a detected signal constituting all of thepulses in sad groups of sad transmitted pulse trains, timing meansresponsive to the leading and trailing edges of each of sad pulses insad detected signal for deriving and separating control pulses from saddetected signal according to sad pulse groups of sad first and secondtransmitted pulse trains, means for operating sad first motor in aforward or reverse direction in response to control pulses according tosad pulse groups in sad first pulse train, and means for operating sadsecond motor in a forward or reverse direction in response to controlpulses according to sad pulse groups in sad second pulse train.

'15. A system for rernotely controliing a crane in accordance with claim14 wherein sad timing means responsive to sad leading and trailing edgesof sad detected signal includes a multivibrator for generating firstgating pulses of uniform pulse width commencing with the trailing edgeof each pulse in sad detected signai, multivibrators for simultaneouslygenerating timing pulses commencing with the leading edge of each pulsein sad detected signal, sad timingpulses being of duration briefly lessthan sad preselected transmitted pulse widths, means for deriving secondgating pulses from the trailing edges of sad timing pulses, and means-for combining sad first and second gating pulses to derive and separatesad control pulses.

16. In combination with a crane having at least first and secondoperating motors, a system for remotely controlling the operation,direction and speed of sad motors comprising an operator-controlledtransmitter iocated away from sad crane, and a crane receiver; sadtransmi-tter having means for generating a carrier signal, firstoperator-controlled switching means for generating a first train ofperiodic pulse groups each of which groups includes a motor actuationpulse having a first width for initiating first motor operation at apredetermined forward speed and having a second width for initiatingfirst motor operaton in reverse at substantially the same speed togetherwith a motor speed control pulse when selective- -ly controlling thespeed of sad first motor at a value other than as predetermined by sadmotor actuating pulse of first or second width, secondoperator-controlled switchng means for generating a second train ofpulse groups of like periodicity each of which groups includes a motoractuation pulse having a third width for initiating second motoroperation at a predetermined forward speed and having a fourth width forinitiating second motor operation in reverse at substantially the samespeed together with a motor speed control pulse when selectivelycontrolling the speed of sad second motor at a va1ue other than aspredetermined by sad motor actuating pulse of third or fourth width, sadpulse groups of sad first pulse train being displaced timewise -from sadpulse groups of sad second pulse train, means for modulating sad carrierwith sad first and second pulse trains, and means for radiating sadmodulated carrier; sad receiver havng means for receiving sad radiatedmodulated carrier and for deriving therefrom a detected signalc-onstituting all of the pulses in sad groups of transmitted pulsetrains, first and second actuating circuits for operating sad firstmotor at predetermined speed in for-ward and reverse directionsrespectively, third and fourth actuating circuits for operating sadsecond motor at predetermined speed in forward and reverse directionsrespectively, means for varying the speed of sad first and secondmotors, timing circuit means responsive to pulses of sad first andsecond width in sad detected signal for respectively operating sad firstand second actuating circuits and responsive to pulses of sad third andfourth width in sad detected signal for respectively operating sad thirdand fourth actuating circuits, means responsive to the presence in saddetected sigma] of pulses of first or second width for selectivelyapplying first motor speed control pulses in sad detected signal to sadmeans for varying the speed of sad first motor, and means responsive tothe presence in sad detected signal of pulses of third or fourth widthfor selectvely applying second motor speed control pulses in saddetected signal to sad means for varying the speed of sad second motor.

17. A system for remotely controlling a crane in accordance with claim16, wherein the width of each of sad motor speed control pulses in sadfirst and second pulse trains is adjus-ted by sad first and secondoperatorcontrolled switching means respectively, speed of the respectivemotor being a function of the respectve speed control pulse width.

18. A system for remotely controllng a crane in accordance with claim17, wherein the width of each of 19 said speed control pulses isadjustable in a predetermined number of increments by said first andsecond operatorcontroiled switching means.

19. A system for remotely controlling a crane in accordance With claim16, and including timing means at said transmitter for separating intime each motor speed control pulse in said first and second pulsetrains from the respective motor actuation pulse, said timing meansproviding a fixed delay in each pulse group between the -trailing edgeof said motor actuation pulse of first, second, third and fourth Widthsand the ieading edge of the respective motor speed control pulse.

20. A system for remotely controlling a crane in accordance With claim19, wherein said third and ourth pulse widths are each greater than saidfirst and second pulse widths, said motor speed control pulsesselectable by said first and second operator-controlled switchng meansbeing of equal minimum and maximum width.

Refererxces Cited by the Examin er UNITED STATES PATENTS Nosker 31816 XHarnschfeger 318-416 Dougherty 31816 X Jeerson et al. 318-16 Shaw 31816X Gimpel et al.

Lovejoy.

Mynall.

Young 31816 15 ORIS L. KADER, Primary Examner.

MILTON 0. HIRSH-FIELD, Examiner.

T. LYNCH, Assistant Examiner.

1. IN COMBINATION WITH A CRANE HAVING THREE OPERATING MOTORS, A SYSTEMFOR REMOTELY CONTROLLING SAID MOTORS COMPRISING AN OPERATOR-CONTROLLEDTRANSMITTER LOCATED AWAY FROM SAID CRANE AND A RECEIVER MOUNTED ON SAIDCRANE; SAID TRANSMITTER COMPRISING MEANS FOR GENERATING A CARRIER SIGNALFIRST OPERATOR-CONTROLLED MEANS FOR GENERATING A FIRST TRAIN OF EVENLYSPACED PULSES, A SECOND OPERATOR-CONTROLLED MEANS FOR GENERATING ASECOND TRAIN OF EVENLY SPACED PULSES DISPLACED TIMEWISE FROM THE PULSESOF SAID FIRST TRAIN; THIRD OPERATOR-CONTROLLED MEANS FOR GENERATING ATHIRD TRAIN OF EVENLY SPACED PULSES DISPLACED TIMEWISE FROM THE PULSESOF SAID FIRST AND SECOND TRAINS, MEANS FOR MODULATING SAID CARRIER WITHSAID PULSE TRAINS, AND MEANS FOR RADIATING THE MODULATED CARRIER; SAIDRECEIVER COMPRISING MEANS FOR RECEIVING THE RADIATED MODULATED CARRIERAND FOR DERIVING THEREFROM A DETECTED SIGNAL CONSTITUTING ALL OF THEPULSES OF SAID PULSE TRAIN, MEANS RESPONSIVE TO ALL OF THE PULSES OFSAID DETECTED SIGNAL TO GENERATE A CONTROL PULSE TRAIN, MEANS RESPONSIVETO ALL OF SAID PULSES IN SAID DETECTED SIGNAL TO GENERATE FIRST, SECONDAND THIRD PULSED TIMING SIGNALS, MEANS RESPONSIVE TO BOTH SAID CONTROLPULSE TRAIN AND SAID FIRST, SECOND AND THIRD PULLED TIMING SIGNALS FOREXTRACTING PULSES ACCORDING TO SAID ORIGINAL FIRST, SECOND THIRDTRANSMITTED PULSE TRAINS, MEANS RESPONSIVE TO EXTRACTED FIRST TRAINPULSES FOR CONTROLLED ONE OF SAID MOTORS, MEANS RESPONSIVE TO EXTRACTEDSECOND TRAIN PULSES FOR CONTROLLING A SECOND ONE OF SAID MOTORS, ANDMEANS RESPONSIVE TO EXTRACTED THIRD TRAIN PULSES FOR CONTROLLING A THIRDONE OF SAID MOTORS.